A Wide-Field Survey of Two z ~ 0.5 Galaxy Clusters: Identifying the Physical Processes Responsible for the Observed Transformation of Spirals into S0s

By S. M. Moran, Richard S. Ellis, T. Treu, Graham P. Smith, R. Rich, I. Smail. 2007

171 citations recorded by the source corpus.

We present new results from our comparative survey of two massive, intermediate-redshift galaxy clusters, Cl 0024+17 (z = 0.39) and MS 0451–03 (z = 0.54). Combining optical and UV imaging with spectroscopy of member galaxies, we identify and study several key classes of “transition objects” whose stellar populations or dynamical states indicate a recent change in morphology and star formation rate. For the first time, we have been able to conclusively identify spiral galaxies in the process of transforming into S0 galaxies. This has been accomplished by locating both spirals whose star formation is being quenched and their eventual successors, the recently created S0s. Differences between the two clusters in both the timescales and spatial location of this conversion process allow us to evaluate the relative importance of several proposed physical mechanisms that could be responsible for the transformation. Combined with other diagnostics that are sensitive to either ICM-driven galaxy evolution or galaxy-galaxy interactions, we describe a self-consistent picture of galaxy evolution in clusters. We find that spiral galaxies within infalling groups have already begun a slow process of conversion into S0s, likely via gentle galaxy-galaxy interactions. The fates of spirals upon reaching the core of the cluster depend heavily on the cluster ICM, with rapid conversion of all remaining spirals into S0s via ram pressure stripping in clusters where the ICM is dense. In the presence of a less dense ICM, the conversion continues at a slower pace, with other mechanisms continuing to play a role. We conclude that the buildup of the local S0 population through the transformation of spiral galaxies is a heterogeneous process that nevertheless proceeds robustly across a variety of different environments.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/f35ad8ab248cf11448f4a75abfb8796284e35905

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Citations in the corpus

The STAGES view of red spirals and dusty red galaxies: Mass-dependent quenching of star formation in cluster infall (2008, background): “The discussion whether the observed S0 galaxies have evolved from spiral progenitors has continued for three decades now (Dressler 1980; Moran et al. 2007).”
Bulge mass is king: the dominant role of the bulge in determining the fraction of passive galaxies in the Sloan Digital Sky Survey (2014, background): “Additionally there is a tendency for galaxies at higher densities to be more bulge dominated and hence have higher Sérsic index and concentration parameters (Dressler 1984, Moran et al. 2007, Tasca et al. 2009).”
LoCuSS: THE SLOW QUENCHING OF STAR FORMATION IN CLUSTER GALAXIES AND THE NEED FOR PRE-PROCESSING (2015, background): “A number of other studies have also argued for relatively long timescales (∼1–4 Gyr) for the quenching of star formation in recently accreted cluster galaxies (Balogh et al. 2000; Moran et al. 2007; Finn et al. 2008; von der Linden et al. 2010; De Lucia et al. 2012; Wetzel et al. 2013).”
BUDHIES II: a phase-space view of H i gas stripping and star formation quenching in cluster galaxies (2015, background): “(e.g. Dressler 1980; Lewis et al. 2002; Gómez et al. 2003; Koopmann & Kenney 2004; Boselli & Gavazzi 2006; Poggianti et al. 2006; Moran et al. 2007; Bamford et al. 2009; Jaffé et al. 2011b).”
Star formation and AGN activity in SDSS cluster galaxies (2009, background): “Although the properties of individual clusters can differ significantly from the average cluster properties, even for clusters with similar masses (Moran et al. 2007), this scatter seems to be mostly stochastic in nature: several studies find that there is no systematic trend of varying galaxy…”
Galaxy Zoo: Passive Red Spirals . (2009, background): “S0s are often argued to be too bright and massive and have too large bulge-disk ratios to simply be faded spirals (e.g. Burstein et al. 2005), but Moran et al. (2007) argue that they have linked passive spirals with young S0s in two z ∼ 0.5 clusters and that a combination of gas stripping and…”
Structure and Kinematics of Early-Type Galaxies from Integral Field Spectroscopy (2016, background): “…that these massive ellipticals were already passive from larger redshift and remain so during their evolution (Stanford et al. 1998; Postman et al. 2005; Tasca et al. 2009), while most of the observed evolution consists of a transformation of spirals into S0s (Smith et al. 2005; Moran et al. 2007).”
The ATLAS3D project - VII. A new look at the morphology of nearby galaxies: the kinematic morphology-density relation (2011, background): “…computed for a sample of eight clusters, as part of the LoCuSS survey, indicating that ram-stripping becomes important insider <∼ r200/3 (Smith et al. 2010, see also Moran et al. 2007), where for Virgo the virial radius isr200 ≈ 1.6 Mpc (Hoffman et al. 1980; McLaughlin 1999; Côté et al. 2001).”
ON THE EVOLUTION OF THE MOLECULAR GAS FRACTION OF STAR-FORMING GALAXIES (2011, methodology): “Physical properties of the galaxies Stellar masses for all the galaxies were determined by fitting the galaxy SED constructed fromBVRIJK imaging (Moran et al. 2007) to a large suite of model SEDs using the KCORRECT software, v4.”
THE RISE AND FALL OF PASSIVE DISK GALAXIES: MORPHOLOGICAL EVOLUTION ALONG THE RED SEQUENCE REVEALED BY COSMOS (2009, background): “While we have specifically attempted to exclude S0s from our disk sample (they are classified as spheroidals), distinguishing them at distant epochs remains difficult (e.g., Moran et al. 2007b).”